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AN ADDRESS 



ON THE 



Natural History and Pathological Osteology 



OF 



THE HORSE, 



DELIVERED BEFORE 



THE ANNUAL MEETING 



Connecticut Board of Agriculture, 

AT MIDDLETOWN, JANUARY, 1870, 
By N: CRESSY, M. D. 



ILLUSTRATED. 

HARTFORD: 

CASE, LOCKWOOD & BRAINARD, PRINTERS. 

1870. 








c^> 






[Extracted from Procedings of Conn. Ag. Society, 1870.] 



The Natural History and Pathological Osteology 



OF 



THE HOKSE. 



By N. Cressy, M. D. 
Lecture delivered January 14th, 1870. 

The horse, in all ages of the world, has been the esteemed 
servant of man both in war and in peace. And to the 
scientific inquirer it is also an object of interest. For this 
noble creature and its allied species, not only afford the 
veterinarian an opportunity of investigating certain rare phe- 
nomena of disease otherwise unknown in the history of the 
Healing Art, but they enable the naturalist to study the inti- 



4 BOARD OF AGRICULTURE. 

mate relations which these few surviving species hold to their 
fossil ancestors, whose remains are profusely strewn in the 
diluvial strata of the earth. 

The domestic horse, zoologically speaking, is known as the 
Equus caballus, and was classed by Cuvier with the other 
thick-skinned and non-ruminating mammals in that compre- 
hensive order Pachydermata ; but which Professor Owen has 
very justly subdivided on account of the three-fold variety in 
the special details of structure thus included, and has placed 
the horse together with all those hoofed animals which have 
an odd number of toes, either one or three, in his well-chosen 
order Perissodactyla, in contradistinction to his even-toed 
order, Artiodactyla, to which our cattle, deer, sheep, and 
swine belong. 

The two preceding orders will be found, by a careful 
analysis, to constitute a natural and well-marked anatomical 
division of all the hoofed quadrupeds, both recent and fossil. 
In view of which fact, naturalists have endeavored to trace 
the ancestry of our equine and bovine races back to the 
ancient prototypes of these two orders, which flourished ex- 
tensively during an earlier epoch of creation. 

But in passing we would observe that though the Gnu or 
"horned-horse" of Africa, very much resembles the wild 
prairie horse in its general bodily conformation, yet it is found, 
by a moment's inspection, to have a divided hoof and all the 
characteristic features of the antelope family, to which it 
belongs. 

The history of the horse-family is veiled in remote antiquity. 
Fossil remains of several extinct, but closely allied species, 
have been found in the Tertiary deposits on both sides of the 
Atlantic. 

There is a fossil skull of an extinct horse, Equus nomadicus, 
in the British Museum, taken by Messrs. Falconer & Cautley 
from the Miocene formations in the Sewalk Mountains of 
India, associated with the remains of gigantic Pachyderms, 
Ruminants, and other extinct mammals, showing that the 
horse in its paleontological lineage antedates the lapse of his- 
toric time. But the most ancient representative of the fossil 



HORSES. 5 

liorso was undoubtedly the Equus primigenius of Meyer, and 
which was also called Hippotherium gracile by Wagner. It 
ranged from the Himalayas to the Alps, and existed from the 
Miocene period, geologically speaking, to the Diluvium, or the 
recent formations. The limbs of a fossil pony, if such we 
may call it, were discovered in the upper Tertiary clay of 
Nebraska, at Antelope Station, on the line of the Union 
Pacific Railroad, in 1868, which were carefully examined and 
described by Prof. 0. C. Marsh, of New Haven, who believed 
that the restored skeleton of this species would not exceed 
two and a half feet in height; and therefore very appropriate- 
ly named it Equus parvulus * This is the seventeenth species 
of fossil horse now known to have been indigenous to this 
continent. Numerous teeth and fragmentary portions of the 
so-called Equus fossilis, which undoubtedly included several 
species that were closely allied to the present horse, have been 
discovered in the Drift in various parts of Europe and 
America. 

Thus it will be seen that the geographical distribution of 
the Equidae in a former period of the earth's history, was 
very extensive in both hemispheres. But it is believed by 
Professor Owen, Darwin, and other distinguished naturalists, 
that this family had been entirely blotted out of the Fauna of 
our part of the globe ere the fall of the footstep of man had 
been heard. According to this view the horse became extinct 
in North America cotemporary with the Mammoth, and in 
South America with the Megatherium. For it is alleged 
that the remains of the primitive horses of the New World 
lie intermingled in the same geological strata with these huge 
quadrupeds, and no intermediate species are found in the 
later formations, thus intimating that the wild horses of to- 
day upon our pampas and prairies, were introduced here in 
the state of domestication by the Spanish colonies in the fif- 
teenth century. While on the other hand it is claimed that 
the recent discoveries in Paleontology seem to indicate that 

-American Journal of Science and Arts, vol. XL VI, November, 1868. 
See Owen's Paleontology, and his History of the British Fossil Mammalia, 
and also the article Equidce in Knight's Cyclopaedia of Natural History. 







BOARD OF AGRICULTURE. 



the equine race has been continuous upon the continent from 
the earliest fossil representatives of this type of animals to 
those of the present clay. But further evidence will be re- 
quired in order to decide such an important question. Yet 
we can see no valid reason why this race may not have con- 
tinued here in the same unbroken series as it appears to have 
done in the Old World. 

But naturalists are agreed that there is no aboriginal or 
truly wild breed of horses now known to exist in any part of 
the globe ; and this is also corroborated by the observations 
of Oriental travelers, who believe that the wild horses of the 
East were once domesticated animals. 

Hence we see that the origin of the domestic horse is veiled 
in great obscurity, and thus becomes one of the most interest- 
ing problems of Natural History. Thomas Bell, in his His- 
tory of the British Quadrupeds, claims that the Egyptians 
were probably the first to break the proud spirit of this noble 
animal, and reduce it to obedience and servitude. While 
others believe that the primitive horse was first domesticated 
in Asia. 

The horse, in its special details of structure, reverts to that 
primitive type of three-toed quadrupeds which appeared upon 

Figure 1. 




the earth among the earliest of the Tertiary mammals, and 
which have, therefore, been very fitly characterised as the 
Paleotheria, or ancient wild beasts. These animals walked 



This plate is copied from Owen's Comparative Anatomy. 
The feet of the Horse, Hipparion and Pakopterium. 



HORSES. 7 

upon their three toes, which correspond to the second, third, 
and fourth rows in the pentadactyle, or five fingered hand, 
as seen at Fig. 1 a. But these Paleotheres eventually faded 
away (at the close of the Eocene period), and were succeeded 
(in the Miocene) by another tri-dactylous quadruped, which, 
on account of its general resemblance to the horse, as shown 
by its fossil bones, has been called the hipparion. And, 
although this horse-like animal had three toes upon each foot, 
the same as its predecessors, yet upon the hard ground it 
really walked upon one, the same as the horse does, inasmuch 
as the outer toes had become considerably shortened, and re- 
duced in size, as is seen at Fig. 1 b. 

The dentition, as well as the close resemblance of the feet, 
point to a transitional position, which the hipparion must have 
occupied in the " survival of the fittest " between the paleo- 
theres and the modern horse. And, believing that this same 
process of " derivative" modification may have been carried 
still further, we should ultimately expect to find a creature in 
which those outer toes were wholly wanting ; and this is 
really the case in all the equine species. Fig. 1 c. " Thus 
the succession in time," says Professor Owen,* " accords 
with the gradational modifications by which paleotherium is 
linked on to equus." 

Hence we see that the so-called " splint-bones," in the 
limbs of the horse are simply the rudiments of those lateral 
toes in the tridactyle feet of their ancient predecessors. 
But occasionally we find a horse with these supplementary 
ancestral hoofs. " In one of the latest examples," says Pro- 
fessor Owen,f " the inner splint-bone, answering to the 
second metacarpal of the pentadactyle foot, supported pha- 
lange^ and a terminal hoof, in position and proportion to the 
middle hoof, resembling the corresponding one in JrijJjJarion" 

Such examples of tridactyle feet in the horse, though 
usually regarded as " monsters," clearly illustrate the natu- 
ral law of hereditary descent. 

There is a great variety in the form of the limbs, or ambu- 

* See his closing chapter on the Anatomy of Vertebrates, vol. iii. 

tin his Comparative Anatomy and Physiology of Vertebrate Animals,! vo. iii, 



8 BOARD OF AGRICULTURE. 

latory appendages of vertebrate animals. In the fin of the 
fish, which is analagous to the human arm, there is a multi- 
plicity of rays, but higher in the series the number is reduced 
to five phalangeal rows, of which the monodactyle foot of the 
horse is the lowest expression, and answers to the middle 
finger of the human hand. 

The law by which these toes are lost is interesting to us, 
as well marked examples of such modifications are found in 
the domestic animals. The first to disappear is the thumb, 
then we have a four-toed foot like the hog and the deer. 
Next, the fifth row, or little finger is lost, and this leaves the 
tridactyle foot, which we have already considered. 

Having thus briefly pointed out a few facts concerning the 
natural history of the horse, let us now turn our attention to 
another department of our subject, which, I trust, will be far 
more interesting to those who have the guardianship of this 
noble animal* But as it is not our mission on this occasion 
to treat of the general maladies of the equine system we will 
limit our inquiries to the pathological, or diseased conditions 
of the bones, and of some of the adjacent tissues. 

Comparative anatomists have clearly shown that the entire 
series of vertebrate animals, including man, are built upon 
the same general plan of structure. The chemist has assured 
us that the bones of all animals are composed of the same 
proximate principles, or ingredients, though the relative quan- 
tities of these several principles vary considerably in the dif- 
ferent types, orders, and species. And the physiologist has 
conclusively proved by his microscopic examinations that the 
blood of fishes, reptiles, birds, and mammals, contains the 
same anatomical granules and cells as is found in the blood 
of man. Now, in view of all these facts, why may we not 
suppose that the domestic animals are afflicted with the same 
diseases as we are, differing only in degree ? 

Upon this basis we shall inquire into the pathological oste- 
ology of the horse, though we do not expect to find all those 
loathsome diseases of the bones in the equine system which 
so frequently visit the frail body of mortal man. 

The diseases of the bones may be divided into three classes. 
First, we will consider those diseased conditions which affect 



HORSES. » 

the nutrition of the bones, and thus compromise the utility of 
the part. A healthy bone is composed of organic and inor- 
ganic matter, which is united in certain definite proportions 
though they relatively vary with age. In certain diseased 
conditions of the system there is a want of the earthy salts, 
phosphate and carbonate of lime, in the blood, and hence the 
bones are deprived of their solidity, and soon become dis- 
torted, as is seen in Rickets. But, on the other hand, there 
may be a surplus quantity of this earthy matter deposited in 
the bones, and thus render them extremely brittle, like the 
fragility of old age. Or an undue absorption of these earthy 
salts may take place, and a softened bone be the result. This 
disease is known as " mollities osseum" and though of rare 
occurrence either in the human or equine system, yet it is fre- 
quently seen in our New England cows in the form of " cripple 
ail," especially in our hill farms, where the soluble phos- 
phates have become nearly exhausted from the soil. The 
desire which cows usually manifest in such localities to chew 
bones is a clear index to the kind of fertilizers which those 
lands most need. The free use of ground bone on such farms 
will effectually cure this Osteomania, and will also prove a 
potent remedy when mixed with the feed to restore this f-rfcsk;. 
and crippled condition of our milch cows. 

Again, both the organic and inorganic elements may become 
partially absorbed, and thus constitute a case of atrophy, or 
perishing of the bone. But this disease is usually local in 
character. 

The second class of bone diseases includes those which in- 
volve the tissue in a simple or scrofulous inflammation. But 
we will only notice under this division those two very com- 
mon affections which are known to pathologists as Necrosis 
and Caries. The first of these, as the word implies, is the 
death of a bone or any part of it, attended by a regenerative 
process, established at the time coeval with the inflammation 
or injury which deprives it of vitality. In this respect it is a 
singular disease, and has nothing analagous to it in the affec- 
tions of the soft parts. While Caries in its degenerative pro- 
cess is very similar to the ulceration of the muscular tissues. 

9 



10 BOARD OP AGRICULTURE. 

In Necrosis a portion of bone dies, which is called a sequestrum, 
and is surrounded by living or germinal matter that will sup- 
ply the place of this diseased portion when it shall have been 
removed by carious ulceration or by a surgical operation. 
Fortunately necrosis is a rare disease in the equine system, 
though very common, as we have before observed, in man. It 
presents a solitary example of an effort on the part of nature 
to counteract or provide against the ravages of disease. In 
this respect it becomes a very interesting subject of inquiry. 

Exostosis is the principal disease in the third class that we 
shall attempt to describe on this occasion. And of all the 
organic maladies of the horse, this is, by far, the most com- 
mon and the one, in view of cure, the most dreaded by the 
veterinarian. In its origin it is either acute or hereditary, 
and in both cases may be transmitted from generation to gen- 
eration with increasing severity, and thus ultimately ruin the 
entire family stock. 

By the term Exostosis we mean an extra bony growth, or 
tumor, which necessarily involves the periosteum or the cover- 
ing of the bone. In this respect we shall radically differ from 
the views of Dr. Porter, who claims (in his article on the 
pathological conditions of bone, in the Cyclopaedia of Anatomy 
and Physiology) that the periosteum is not affected in this 
disease, but we will not stop to discuss the matter here, for 
an appeal to the facts concerning its genesis will satisfy even 
the doubting mind of every earnest inquirer. In a case of 
acute exostosis, or where it is primarily developed without 
any hereditary predisposition on the part of the immediate 
parentage ; this disease usually occurs as the result of an in- 
jury, either from a blow or a strain. An inflammation follows 
and an extra quantity of blood, laden with salts of lime, is 
brought to the part, and thus the periosteum and the surround- 
ing tissues is thoroughly congested. Eventually the phos- 
phate and carbonate of lime becomes deposited within tlie 
periosteum at the seat of injury, and a hard, unyielding, 
bony tumor is the inevitable result. In fact, ringbone, splint, 
and spavin arc only different names of the result of this same 
morbid process of bony growth. All of these affections may 



HORSES. 



11 



Figure 2. 



be developed from similar exciting causes or from an inherited 
constitutionality. 

Every bone in the normal condition of nutrition grows 
large by the deposition of new material upon its external sur- 
face through the instrumentality of the periosteum. And 

any agency which will increase the 
flow of blood to that part and thus 
unduly excite the action of this mem- 
brane, will cause this excessive and 
morbid production of bone. But 
there is evidently a certain peculiar- 
ity in the general nutrition of the 
body, favorable to the production of 
this disease ; for it is often seen, 
even fearfully developed, in the colt 
at an early age, where no external 
or exciting cause could have played 
its part. Such a condition of the 
system might well be termed, in the 
language of pathology, an exostosi- 
cal diathesis. 

Though every bone in the skeletal 
frame-work of the horse is liable to 
an attack of exostosis, yet the joints 
are the most frequently the seat 
rheumatism, or " founder, " which 
periosteum of the bones of the 
chest, you will occasionally find, upon post-mortem ex- 
amination, that the lower end of the ribs and their appendages 
are affected with this same malady. At Figure 2 will be seen 
a case of "chest-founder," so called, in which the first and 
second ribs of the right side are firmly grown together, and 
are attached by a bony union to the first rib of the opposite 
side. This specimen was taken from a horse thirty years of 
age, which was noted for its general usefulness, yet we imagine 
that this creature must have suffered in its respiratory func- 
tions, inasmuch as the anterior part of the thorax, or chest, 
was a solid bone hoop. May not this form of the disease ac- 




" Chest Founder." 

of this disease. In 
usually involves the 



12 



BOARD OF AGRICULTURE. 



count for many cases of "heaves," "short-breath," &c. ? 
Such a case would not be amenable to any treatment, unless 
taken in hand early and with a clear conception of the ap- 
proaching malady. 

Ringbone derives its name from the peculiar form which 
this morbid growth of bone assumes when it attacks the pas- 
tern joint ; a well marked example of which will be seen in 

Fijrure 3. 









Ringbone. 

the plate at Figure 3. The incidental causes of ringbone are 
very numerous. Almost any injury received upon the pastern 
bone may give rise to a more or less aggravated form of this 
disease, if not promptly attended to, with perfect rest secured 
for the animal. Such cases should be freely treated with 



Figure 3. — Ringbone; s, upper pastern; 6, lower pastern; c, coffin bone. 



HORSES. 13 

quieting and cooling lotions, in view of arresting the conges- 
tion or extra flow of blood to the part, that inevitably fol- 
lows, as the result of injury, and which causes the swelling, 
heat, and pain so grievous to be borne by the poor afflicted 
animal. And as a remedy to alleviate the suffering and con- 
trol the progress of the disease, I would earnestly recommend 
a preparation of Colorless Iodine Liniment that I have used 
for several years with marked success in human and veteri- 
nary practice. Cases of hereditary ringbone that appear 
early in a colt need no treatment, for their only cure consists 
in hastening the anchylosis of the joint, which, of course, 
forever obliterates the freedom of motion there, by soldering 
the two articulating bones together in firm osseous union. 
Even with such a cure the creature ceases to limp, because the 
impaired motion of the joint that caused such excruciating 
pain in walking has been destroyed. And though a horse 
with such an impediment would readily stumble, and thus be 
worthless for the turf, yet with careful usage upon light draft 
it may be serviceable for many years. 

Percival divides the causes of ringbone into three classes, 
as follows, "hereditary, structural, and incidental"; the first 
and last of which wfi have already noticed, and the second we 
will now consider. ^Though the feet and limbs of all the 
equine family contain the same number of muscles and bone^f 
yet the form and arrangement of these parts are not always- 
the same in all the various breeds. In the race-horse the 
pastern bones stand quite obliquely, as is seen in the Eclipse 
at Figure 4, in order that the foot will rebound from the turf 
with an elastic spring when vieing for the goal. Such con- 
structed feet are not commonly the seat of ringbone, inas- 
much as the weight of the body is not directly felt upon the 
coffin-bones. But on the other hand, when the pasterns are 
nearly erect, the heft of the body in the act of trotting, falls 
as a dead weight upon the bones of the feet, and thus a con- 
stant irritation is kept up in the periosteum of the part, until 
a ringbone is the result. Horses with such formed feet should 
be carefully used, and then, never upon the pavements. Such 
examples illustrate that hereditary predisposition to ringbone, 



14 BOARD OF AGRICULTURE. 

splint, and spavin, which should ever be avoided in choosing 
your breeding stock. 

That disease which is known as "splint" is of very com- 
mon occurrence, and yet it is not grave in its consequences 
when not complicated by other diseases. It is very simple in 

Fig. 4. 




1 
I 



"Eclipse. 

its nature, origin, and treatment; andRonsists in the grow- 
flfcing of the splint-bone on to the cannon-bone by this same 
morbid process of exostosis, which is usually the result of ai#* 
external injury. 

The hind and forward limbs are alike subject to this dis- 
ease. 

"Splint" seldom occasions much lameness, except in its 
primary stage, when the cushion of fibro-cartilage that is in- 
terposed between the splint and cannon-bones becomes in- 
volved in an ossific inflammation. But when these parts 
are firmly united in bony union, no further pain or lameness 
will be experienced by the creature. At this stage of the 
disease treatment of course is useless ; but in the commence- 
ment give the horse rest and apply cooling lotions to allay 
the inflammation. 

In a case of long standing, and even in one having a well- 

♦Photographed from the plate in Oamgec &■ Law's Veterinary Anatomy 



HORSES. 15 

marked tumor, the pain and lameness may be relieved by the 
moderate application of the tincture of cantharides. But some 
cases will not recover until the Blister has been applied, 
when that intervening cartilage will be converted into bone ; 
then the cure is done. 

When exostosis attacks the tarsus or instep just below the 
hock-joint, it is called spavin. The first symptoms in this 
form of the disease are not usually recognized in their true 
light, and the horse is urged on in its daily toil until the pain 
becomes so excruciating that the poor creature can no longer 
endure such suffering. In a majority of cases this disease 
occurs from hereditary transmission. It is more frequent 
than ringbone, inasmuch as its predisposition is more easily 
awakened by an exciting cause. 

The six bones of the tarsus are separated from each other 
by a layer of inter-articulating cartilage, and the undue pres- 
sure which is brought to bear upon this part of the limb when 
the horse is heavily laden upon the ascending pavement, 
causes more or less irritation, and thus congestion and inflam- 
ination ensues. 

The first two tarsal bones that grow together in this disease 

are those which anatafriists have called the scaphoid and the en- 

tocuniform. In fact rHs rare to find an old th;ay-horse in which 

^^these bones are^ot consolidated in one, even when there 

no sign of disease among the other tarsal bones. But if t 



I 



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, it i! 



disease is not arrested here, either by a resolution of Natur 
or by treatment, it usually involves the adjoining parts in tin' 
same inflammation, and thus ultimately anchjlose the entire 
tarsus, together with two^^hs and the cannon-bone, in firm 
and indissoluble union. Such a case is beyond the help of 
the Healing Art, and any attempt to " cure" will exhibit the 
ignorance or deception of its vain pretender. 

The general plan of treatment for Spavin is the same as 
for Ringbone and other forms of exostosis. In the early stage 
of the disease is your only hope of cure. But when the dis- 
ease has advanced to that degree where new bone begins to 
lie formed within the cartilage and periosteum, it is hard to 
be controlled : even then it may lie partially arrested in its 



r 



1'» BOARD OP AGRICULTURE. 

progress by the free use of iodine and counter-irritants, such 
as the different preparations of Spanish Flics. 

Blistering is a potent agent in judicious hands, but it must 
not be used indiscriminately ; for many of its supposed cures 
are nothing but an anchylosis of the joint, as was seen in the 
case of the " cured" Ringbone, Figure/*? 3 

The old adage that " an ounce of prevention is worth more 
than a pound of cure,'" is constantly verified in stock raising. 
And lierc let me impress upon your minds that the only way 
to ameliorate this diseased condition of the horse is to breed 
from pure blooded animals, and occasionally interchange with 
foreign stock. 

Whenever it is your unhappy lot to have one of these poor 
afflicted creatures, treat it with kind and humane care. And 
be not imposed upon by the pretending " Horse Doctor," who 
perchance may happen at your door, and earnestly assure you 
that by the extracting of a certain " bladder " from the hor*e*s 
foot the Ringbone will be forever cured. Believe it not, for 
it is a baseless imposition. 

Neither listen to him who talks of a " leakage of the joint,' 
and attempt to cure accordingly, for such assertions have no 
foundation whatever. ^ 

The nature, cause, and general treatment of all these afiec- 
ns have now been briefly indicated ; and henceforth it re- 
ams for you to imbibe the useful and the good and apply ir' 

o practice. j^ 

c 



4 



.* 



00T 14 1870 






AN ADDRESS 



Natural History and Pathological Osteology 



THE HORSE, 

DELIVERED BEFORE 

THE ANNDAL MEETING 

OF THE 

Connecticut Board of Agriculture, 

AT MIDDLETOWN, JANUARY, 1870, 
>By N. CRESSY, M. D. 



ILLUSTR ATED 



HARTFORD: 

CASE, LOCKWOOD & BRAINARD, PRINTERS. 

1870. 



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